When I plan to go and stay somewhere in England I like to know before hand what the pubs are like in the vicinity. I look for pubs that are family friendly because we have the kids with us and pubs are where we tend to eat our evening meals so I like to have an idea about what menus are on offer. Of course I also want to know what pubs are likely to offer a quality selection of Ales.
The cask Marque website is very usefull as you can determine what pubs have been accredited and this should be a guarantee of quality. Their website really could do with updating but it is a good starting point.
There are plenty of pub review sites on the net to search through. Many of these are very limited on the amount of info they offer and have far few reviews available. The site that seems to be most comprehensive is Beer in the Evening which I find gives me a far better success rate than any of it's competitors. It is a user friendly site but ultimately you are at the mercy of the users who have made the reviews.
Out of the thousands of people who step foot through the doors of these pubs you may get reviews from about 6 or 7 people which is really just a drop in the ocean. As people tend to be more vocal in their disaproval of things than they do in their appraisal it is likely that many of the reviews are going to be critical. The pub experience is a very personal experience and what is an issue for one might not be for another. There is also the suspicion that when a glowing review is left that is has been made by a propietor or member of staff. Ratings aren't helpful too because they don't show what exactly points are being given too or what is being scored down for.
More and more pubs have there own websites now. For me these are the best way to find out about a pub even if they don't offer a critical view of the establishment. A good site will have plenty of pictures from inside and outside of the pub. For pubs that serve food at least a sample menu should be a given. Upcoming events or a news page is a usefull addition and is good way of gauging the kind of atmosphere you can expect. What is sadly lacking on a lot of sites is information about the beers they serve. This may indicate that the pubs doesn't offer anything to crow about but often it is just a sad oversite.
Not enough pubs have their own websites yet but this does seem to be something that is changing quite fast and hopefully the quality of the sites will improve as well. I also hope that pub review sites can increase their quality dramatically because for me they have a long way to go yet.